1 23 Water Resources Management An International Journal - Published for the European Water Resources Association (EWRA) ISSN 0920-4741 Water Resour Manage DOI 10.1007/s11269-012-0170-6 Statistical Downscaling of River Runoff in a Semi Arid Catchment S. Samadi, Gregory J. Carbone, M. Mahdavi, F. Sharifi & M. R. Bihamta